Immunoregulatory Effects of L-Arginine and Therapeutical Implications

Abstract

Arginine, initially classified as a non-essential amino acid, participates to multiple biological processes including release of several hormones, collagen synthesis during wound healing, antitumor and antibacterial activities and non-specific immunity. Nitric oxide synthase and arginase competes for L-arginine as a substrate and this event appears to play a key role in the regulation of the inflammatory process. In this framework recent studies have identified complex patterns of interactions among these enzymes. This review will emphasizes some effects of L-arginine on immune cell functions, including triggering of L-arginine-nitric oxide and arginase pathways, its biological properties and therapeutical applications.

Vibrational spectroscopic studies of L‐argininium dinitrate

“…The characteristic wavenumbers of these groups are expected to undergo changes in their intensity and position according to their environment. Figure 2 shows the FTIR spectrum of L-argininium dinitrate recorded in the range 4000-400 cm 1 . The high-wavenumber region of the spectrum consists of bands due to NH 3 C , NH 2 , CH 2 and (C)O-H stretching vibrations.…”

“…Under this, it has C 3v symmetry and its normal modes of vibrations are 1 Raman active. 17 In the Raman spectrum, the mediumintensity bands around 1688 and 1594 cm 1 are attributed to the asymmetric and symmetric deformation modes of the -[NH 3 ] C moiety, respectively.…”

“…When the carbonyl group is not hydrogen bonded as mentioned above, a band appears at around 1735 cm 1 in both the infrared and Raman spectra. 18 L-Argininium dinitrate has a characteristic >C O group which gives rise to a very strong and broad band at ¾1729 cm 1 in the infrared spectrum and the corresponding Raman line has a medium intensity at 1734 cm 1 . The fact that this is well within the expected wavenumber range of the carbonyl stretching mode indicates that the >C O is unlikely to be involved in the hydrogen bonding.…”

“…Of the skeletal vibrations, the C-C stretching absorptions occur in the region 1260-700 cm 1 and are normally weak. The C-C deformation bands occur below 600 cm 1 and these also are weak.…”

“…Recent studies have emphasized on some of the effects of L-arginine on immune cell functions, including triggering of L-arginine-nitric oxide and arginase pathways, its biological properties and therapeutic applications. 1 Infrared and Raman spectroscopic studies give structural and bonding features of the crystalline environment and the changes due to biological functioning. Dhanaraj et al 2 investigated the vibrational spectroscopic study of L-arginine phosphate monohydrate (LAP), a new organic non-linear crystal.…”